Arrays
PHP Manual

in_array

(PHP 4, PHP 5)

in_array — Checks if a value exists in an array

Description

bool in_array ( mixed $needle , array $haystack [, bool $strict ] )

Searches haystack for needle and returns TRUE if it is found in the array, FALSE otherwise.

If the third parameter strict is set to TRUE then the in_array() function will also check the types of the needle in the haystack .

Note: If needle is a string, the comparison is done in a case-sensitive manner.

Note: In PHP versions before 4.2.0 needle was not allowed to be an array.

Example#1 in_array() example

<?php
$os 
= array("Mac""NT""Irix""Linux");
if (
in_array("Irix"$os)) {
    echo 
"Got Irix";
}
if (
in_array("mac"$os)) {
    echo 
"Got mac";
}
?>

The second condition fails because in_array() is case-sensitive, so the program above will display:

Got Irix

Example#2 in_array() with strict example

<?php
$a 
= array('1.10'12.41.13);

if (
in_array('12.4'$atrue)) {
    echo 
"'12.4' found with strict check\n";
}

if (
in_array(1.13$atrue)) {
    echo 
"1.13 found with strict check\n";
}
?>

The above example will output:

1.13 found with strict check

Example#3 in_array() with an array as needle

<?php
$a 
= array(array('p''h'), array('p''r'), 'o');

if (
in_array(array('p''h'), $a)) {
    echo 
"'ph' was found\n";
}

if (
in_array(array('f''i'), $a)) {
    echo 
"'fi' was found\n";
}

if (
in_array('o'$a)) {
    echo 
"'o' was found\n";
}
?>

The above example will output:

'ph' was found 'o' was found

See also array_search(), array_key_exists(), and isset().


Arrays
PHP Manual